In the assembly of prewind cameras, such as the so-called single-use camera manufactured by Eastman Kodak Company and Fuji Photo Ltd., it is desired to have the unexposed film predisposed in the form of a roll and placed in a chamber on one side of the camera body before the customer receives the product. As the customer sequentially exposes the film, it is advanced into a lighttight film cartridge or cassette located in a separate chamber on the other side of the camera body, relative to an exposure station. After all of the exposures have been taken, the camera is returned to a photo finisher for processing at which time the camera body is opened under ordinary or white light conditions because the film is protected inside a lighttight container; that is, the film cartridge.
According to U.S. Pat. No. 4,972,649, among others, the loading of film for a prewind camera is typically accomplished by first unwinding the film by withdrawing the unexposed film from its original lighttight cartridge and then creating a film roll inside the camera body, or creating a film roll outside the camera body and then inserting the formed film scroll, that is, the cartridge and the associated film roll into the camera body.
A number of disadvantages are created by using either method described above. Consider the instance where the film is prewound prior to loading the scroll into the camera body. If the cartridge is of the thrusting type, such as described in U.S. Pat. Nos. 5,031,852, and 5,347,334, among others, in which the film leader does not protrude, but rather must be thrust from the interior of the cartridge onto a film take-up spool or winding quill, then the lighttight door of the cartridge must first be opened prior to advancing the film and the film must then be wound out of the cartridge.
For film advance, the film thrusting and the film winding operations are each speed limited, and must be done in a sequential order. Therefore, the cycle time for film loading is affected adversely. Winding speed is limited due to the fear that film abrasions and scratches may develop upon the film exiting the cartridge opening. Additionally, the exit path of the film is curved from the cartridge and is not straight, making tension control of the process highly impractical. In addition, the film scroll is formed with the emulsion side facing downward, making mechanical support and guiding of the film during winding difficult.
If the film is wound from the cartridge into a film roll after insertion into the body of the single-use camera, similar problems exist. Winding speed is limited by contact between the emulsion side and the camera body. It is also difficult to guide the film leader across the camera body to form a scroll. The camera design must accommodate the tooling that is required to perform this process. For example, there must be access for a winding quill or shaft to enter the camera body for scroll making.